From 76b0f1337690d223811c852ad3a5078eb89276c5 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Wed, 23 Jun 2010 15:46:55 +1000 Subject: powerpc, hw_breakpoint: Cooperate better with other single-steppers The code we had to clear the MSR_SE bit was not doing anything because the caller (ultimately single_step_exception() in traps.c) had already cleared. Instead of trying to leave MSR_SE set if the TIF_SINGLESTEP flag is set (which indicates that the process is being single-stepped by ptrace), we instead return NOTIFY_DONE in that case, which means the caller will generate a SIGTRAP for the process. Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/hw_breakpoint.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'arch/powerpc/kernel/hw_breakpoint.c') diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index 241e09712314..5a1d55d06a08 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -304,15 +304,16 @@ int __kprobes single_step_dabr_instruction(struct die_args *args) if (!bp_info->extraneous_interrupt) perf_bp_event(bp, regs); + set_dabr(bp_info->address | bp_info->type | DABR_TRANSLATION); + current->thread.last_hit_ubp = NULL; + /* - * Do not disable MSR_SE if the process was already in - * single-stepping mode. + * If the process was being single-stepped by ptrace, let the + * other single-step actions occur (e.g. generate SIGTRAP). */ - if (!test_thread_flag(TIF_SINGLESTEP)) - regs->msr &= ~MSR_SE; + if (test_thread_flag(TIF_SINGLESTEP)) + return NOTIFY_DONE; - set_dabr(bp_info->address | bp_info->type | DABR_TRANSLATION); - current->thread.last_hit_ubp = NULL; return NOTIFY_STOP; } -- cgit v1.2.1